At night hummingbirds must enter the state of torpor, which is a state similar to hibernation or a sleep-like state to ensure that they do not starve to death before dawn. I was recently asked about the length of time it takes a hummingbird to go from a state of torpor to an active state. This is what prompted today’s post.
It can can take as long as an hour for a hummingbird to awaken from a state of torpor and return to an active state. This can also happen more quickly depending on how deep the bird’s state of torpor. In that sense, hummingbirds seem to be a lot like humans because not all of us awaken as quickly as others do.
Torpor allows a hummingbird to conserve energy. In this state the hummingbird’s body temperature may drop by as much as 50 degrees, its heart rate can decrease from 500 beats per minute to less than 50 beats per minute and the bird may even stop breathing for brief period of time. While in a state of torpor, a hummingbird can use as much as 50 times less energy then when in an active state.
The ability to enter a state of torpor is vital to the hummingbird because it ensures that the hummingbird does not literally starve to death before dawn. There is however one risk to a hummingbird in this state and that is the bird’s inability to respond to emergencies while in this state.